Do you know your own strength?

"You hit me harder!"
"No, you did!"
Scientists have found that when someone hits back, they are using more force than they think they are.
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When two kids get in trouble for fighting, both of them often claim that the other hit them harder. It sounds like a lame excuse, but both kids might actually be telling what they think is the truth. A new study suggests that when people hit back, they're using more force than they think they are.

A team of scientists led by Daniel Wolpert of University College London wanted to know why physical fights tend to get more violent as they go on. They asked pairs of volunteers to take turns pressing each other's fingers, both using the same amount of force. Although they didn't realize it, the volunteers actually pushed back with more force than they received. By the end, both volunteers were using much more pressure than they had at the beginning, just like people tend to do when they fight. The researchers describe their study in the July 11, 2003 issue of the journal Science, published by AAAS, the science society.

A possible explanation may be that the brain pays less attention than normal to the body's own movement. This may help the brain stay alert to sensations caused by other people or objects. The brain's ability to focus like this may have evolved because it helped our ancestors protect themselves.